Twelve bacterial isolates, four of them assigned to the genus Acinetobacter, were taken from sewage of a treatment plant with Enhanced Biological Phosphorus Removal (EBPR) and screened for phosphorus uptake, polyphosphate (polyP) accumulation and adsorption under limited carbon and nitrogen conditions. In addition, poly-β-hydroxyalkanoate (PHA) production was studied under carbon, nitrogen, phosphorus, and oxygen limitation. Under C limitation, the uptake of phosphorus was highest, ranging up to 66 mg P per g dry weight (dw) for the Acinetobacter isolates, whereas the highest amount of polyP was detected under limited N conditions (up to 25 mg PolyP / g dw). Extra-cellular polyP was detected, however to a minor extent, accounting for a maximum of 10% of the total polyP in one Acinetobacter isolate. The highest PHA concentration (given as 3-hydroxybutyrate, 3 HB) with 211 mg 3 HB / g dry weight (21% of the dried cell mass) was found for A. johnsonii 120 under nitrogen limitation, but also under P and O2 limitation, PHA, mainly poly-β-hydroxybutyrate and poly-β-hydroxyvalerate, were produced. Three isolates, assigned to the genus Pseudomonas, showed even higher values (345–427 mg 3 HB / g dw) under N limitation. Studies with Acinetobacter johnsonii 120 in continuous culture, simulating the aerobic/anaerobic periods of a waste-water treatment plant, resulted in a P elimination of 36% at an anaerobic contact time of 0.6 h. This value increased to 51% at an anaerobic contact time of 3.1 h. No release of phosphate and no uptake of acetate could be detected during the anaerobic period. In addition, Acinetobacter johnsonii 120 was not able to synthesize PHA under anaerobic conditions. By changing the anaerobic conditions to aerobic, a continuous decrease of the polyP content relative to the totalP content from 45% (day 1 of the aerobic process) to 19% (day 17 of the aerobic process) was observed. The amount of PHA increased to 50.4 mg 3 HB/g dw under aerobic conditions. The results indicate again that the EPBR process cannot be defined by simply applying the knowledge of the metabolic processes, observed or assumed in Acinetobacter pure cultures, to the complexity of the process in sewage treatment plants.
从某生物除磷装置(EBPR)污水中分离出12株细菌(其中4株为不动杆菌属)，对其在有限碳氮条件下的磷吸收、聚磷(polyP)积累和吸附进行了筛选。此外，还研究了碳、氮、磷和氧限制下聚β-羟基烷酸酯(PHA)的生产。在C限制条件下，不动杆菌分离株的磷吸收量最高，可达66 mg P / g干重(dw)，而在有限N条件下，息肉P的吸收量最高(可达25 mg polyP / g dw)。胞外息肉也检出，但检出程度较低，最多只占一株不动杆菌总息肉的10%。在氮限制条件下，约翰氏单胞杆菌120产生的PHA浓度最高，为211 mg 3 HB / g干重(占干细胞质量的21%)，但在P和O2限制条件下，产生的PHA主要为聚β-羟丁酸酯和聚β-羟戊酸酯。在氮限制下，假单胞菌属的三个分离株显示出更高的值(345-427 mg 3 HB / g dw)。在模拟污水处理厂好氧/厌氧时期的连续培养中，对约氏不动杆菌120进行了研究，结果表明，在厌氧接触时间为0.6 h时，P的去除率为36%，在厌氧接触时间为3.1 h时，P的去除率增加到51%。在厌氧期间，没有检测到磷酸盐的释放和乙酸的吸收。此外，约氏不动杆菌120在厌氧条件下不能合成PHA。通过将厌氧条件改为好氧条件，观察到polyP含量相对于总p含量从45%(好氧过程第1天)持续下降到19%(好氧过程第17天)。在好氧条件下，PHA的数量增加到50.4 mg 3 HB/g dw。结果再次表明，EPBR过程不能通过简单地将代谢过程的知识(在不动杆菌纯培养物中观察到或假设)应用于污水处理厂过程的复杂性来定义。
{"title":"Studies on polyphosphate and poly-β-hydroxyalkanoate accumulation in Acinetobacter johnsonii 120 and some other bacteria from activated sludge in batch and continuous culture","authors":"D. Weltin, D. Hoffmeister, W. Dott, P. Kämpfer","doi":"10.1002/ABIO.370160202","DOIUrl":"https://doi.org/10.1002/ABIO.370160202","url":null,"abstract":"Twelve bacterial isolates, four of them assigned to the genus Acinetobacter, were taken from sewage of a treatment plant with Enhanced Biological Phosphorus Removal (EBPR) and screened for phosphorus uptake, polyphosphate (polyP) accumulation and adsorption under limited carbon and nitrogen conditions. In addition, poly-β-hydroxyalkanoate (PHA) production was studied under carbon, nitrogen, phosphorus, and oxygen limitation. Under C limitation, the uptake of phosphorus was highest, ranging up to 66 mg P per g dry weight (dw) for the Acinetobacter isolates, whereas the highest amount of polyP was detected under limited N conditions (up to 25 mg PolyP / g dw). Extra-cellular polyP was detected, however to a minor extent, accounting for a maximum of 10% of the total polyP in one Acinetobacter isolate. The highest PHA concentration (given as 3-hydroxybutyrate, 3 HB) with 211 mg 3 HB / g dry weight (21% of the dried cell mass) was found for A. johnsonii 120 under nitrogen limitation, but also under P and O2 limitation, PHA, mainly poly-β-hydroxybutyrate and poly-β-hydroxyvalerate, were produced. Three isolates, assigned to the genus Pseudomonas, showed even higher values (345–427 mg 3 HB / g dw) under N limitation. Studies with Acinetobacter johnsonii 120 in continuous culture, simulating the aerobic/anaerobic periods of a waste-water treatment plant, resulted in a P elimination of 36% at an anaerobic contact time of 0.6 h. This value increased to 51% at an anaerobic contact time of 3.1 h. No release of phosphate and no uptake of acetate could be detected during the anaerobic period. In addition, Acinetobacter johnsonii 120 was not able to synthesize PHA under anaerobic conditions. By changing the anaerobic conditions to aerobic, a continuous decrease of the polyP content relative to the totalP content from 45% (day 1 of the aerobic process) to 19% (day 17 of the aerobic process) was observed. The amount of PHA increased to 50.4 mg 3 HB/g dw under aerobic conditions. The results indicate again that the EPBR process cannot be defined by simply applying the knowledge of the metabolic processes, observed or assumed in Acinetobacter pure cultures, to the complexity of the process in sewage treatment plants.","PeriodicalId":7037,"journal":{"name":"Acta Biotechnologica","volume":"24 1","pages":"91-102"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82195002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Recovery of bioproducts. EFB study report of the working party on down-stream processing. London: Society of Chemical Industry, 130 pages £ 25.00 (softcover). ISBN 0-901001-79-1","authors":"K. Soyez","doi":"10.1002/ABIO.370160403","DOIUrl":"https://doi.org/10.1002/ABIO.370160403","url":null,"abstract":"","PeriodicalId":7037,"journal":{"name":"Acta Biotechnologica","volume":"6 1","pages":"236-236"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73554641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Viable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small-scale cultivation tests (50 1) with Cd-resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died. Non-viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by-products changes only insignificantly. Their low price makes them economical.
{"title":"Heavy metal sorption by microalgae","authors":"E. Sandau, P. Sandau, O. Pulz","doi":"10.1002/ABIO.370160402","DOIUrl":"https://doi.org/10.1002/ABIO.370160402","url":null,"abstract":"Viable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small-scale cultivation tests (50 1) with Cd-resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died. Non-viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by-products changes only insignificantly. Their low price makes them economical.","PeriodicalId":7037,"journal":{"name":"Acta Biotechnologica","volume":"1 1","pages":"227-235"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77395383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Bley, K. Albrecht, D. Miethe, V. Riis, W. Babel
The remediation of polluted soils by microbial communities is a complex process, characterized by many competitive and cooperative mutual relations between the individual organisms. For the overall characteristic of such processes, top-down systems analyses promise a better description for prognostic aims than bottom-up approaches. This is demonstrated using the EVOLON model to fit the cumulative O2 consumption data of a microbial ecosystem metabolizing diesel fuel in polluted soil. The EVOLON is a generic top-down model providing close approximation to the experimental data. The advantage of using this model instead of other similar models is demonstrated by a comparison of the deviations between model values and experimental data (residuals).
{"title":"Describing microbial degradation processes with the EVOLON model","authors":"T. Bley, K. Albrecht, D. Miethe, V. Riis, W. Babel","doi":"10.1002/ABIO.370160404","DOIUrl":"https://doi.org/10.1002/ABIO.370160404","url":null,"abstract":"The remediation of polluted soils by microbial communities is a complex process, characterized by many competitive and cooperative mutual relations between the individual organisms. For the overall characteristic of such processes, top-down systems analyses promise a better description for prognostic aims than bottom-up approaches. This is demonstrated using the EVOLON model to fit the cumulative O2 consumption data of a microbial ecosystem metabolizing diesel fuel in polluted soil. The EVOLON is a generic top-down model providing close approximation to the experimental data. The advantage of using this model instead of other similar models is demonstrated by a comparison of the deviations between model values and experimental data (residuals).","PeriodicalId":7037,"journal":{"name":"Acta Biotechnologica","volume":"11 6 1","pages":"237-244"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85254072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Toluene was anaerobically degraded by an enriched mixed culture under methanogenic conditions. The mixed culture was originally developed from cow-dung and sludge from a laboratory reactor, in which benzene was anaerobically degraded by sulphate-reducing bacteria. First the mixed culture was enriched on toluene over a year with and without the use of sulphate in the medium. For the evaluation of growth-kinetic and maintenance parameters, namely μ max , K S , k d and Y o X/S , the anaerobic degradation of toluene was carried out in batch as well as in continuous reactor systems. The gas volume and the methane content in the produced gas was somewhat lower than the theoretical value expected, indicating an incomplete degradation of some of the complex intermediates of the toluene degradation pathway. However, the mixed culture was able to transform 41.3% of the toluene carbon into methane.
在产甲烷条件下，通过富集混合培养厌氧降解甲苯。混合培养最初是从实验室反应器中的牛粪和污泥中开发出来的，其中苯被硫酸盐还原菌厌氧降解。首先，在培养基中添加和不添加硫酸盐的情况下，对混合培养物进行了一年多的甲苯富集。为了评估生长动力学和维持参数，即μ max、K S、K d和Y o X/S，在间歇式和连续式反应器系统中进行了甲苯的厌氧降解。产气体积和甲烷含量均低于理论值，表明甲苯降解途径中部分复杂中间体降解不完全。然而，混合培养能够将41.3%的甲苯碳转化为甲烷。
{"title":"Kinetic study of the anaerobic degradation of toluene by a mixed culture","authors":"B. K. Chaduhri, B. K. Chaduhri, U. Wiesmann","doi":"10.1002/ABIO.370160105","DOIUrl":"https://doi.org/10.1002/ABIO.370160105","url":null,"abstract":"Toluene was anaerobically degraded by an enriched mixed culture under methanogenic conditions. The mixed culture was originally developed from cow-dung and sludge from a laboratory reactor, in which benzene was anaerobically degraded by sulphate-reducing bacteria. First the mixed culture was enriched on toluene over a year with and without the use of sulphate in the medium. For the evaluation of growth-kinetic and maintenance parameters, namely μ max , K S , k d and Y o X/S , the anaerobic degradation of toluene was carried out in batch as well as in continuous reactor systems. The gas volume and the methane content in the produced gas was somewhat lower than the theoretical value expected, indicating an incomplete degradation of some of the complex intermediates of the toluene degradation pathway. However, the mixed culture was able to transform 41.3% of the toluene carbon into methane.","PeriodicalId":7037,"journal":{"name":"Acta Biotechnologica","volume":"70 1","pages":"31-41"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89143360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Molecular evolution has recently been applied in biotechnology which consist of the development of evolutionary strategies in the design of biopolymers with predefined properties and functions. At the heart of this new technology are the in vitro replication and random synthesis of RNA or DNA molecules, producing large libraries of genotypes that are subjected to selection techniques following DARWIN's principle. By means of these evolutionary methods, RNA molecules were derived which specifically bind to predefined target molecules. Ribozymes with new catalytic functions were obtained as well as RNA molecules that are resistant to cleavage by specific RNases. In addition, the catalytic specificities of group I introns, a special class of ribozymes, were modified by variation and selection. Efficient applications of molecular evolution to problems in biotechnology require a fundamental and detailed understanding of the evolutionary process. Two basic questions are of primary importance: (i) How can evolutionary methods be successful as the numbers of possible genotypes are so large that the chance of obtaining a particular sequence by random processes is practically zero, and (ii) how can populations avoid being caught in evolutionary traps corresponding to local fitness optima? This review is therefore concerned with an abridged account of the theory of molecular evolution, as well as its application to biotechnology. We add a brief discussion of new techniques for the massively parallel handling and screening of very small probes as is required for the spatial separation and selection of genotypes. Finally, some imminent prospects concerning the evolutionary design of biopolymers are presented.
{"title":"Evolutionary biotechnology-theory, facts and perspectives","authors":"P. Schuster","doi":"10.1002/ABIO.370160102","DOIUrl":"https://doi.org/10.1002/ABIO.370160102","url":null,"abstract":"Molecular evolution has recently been applied in biotechnology which consist of the development of evolutionary strategies in the design of biopolymers with predefined properties and functions. At the heart of this new technology are the in vitro replication and random synthesis of RNA or DNA molecules, producing large libraries of genotypes that are subjected to selection techniques following DARWIN's principle. By means of these evolutionary methods, RNA molecules were derived which specifically bind to predefined target molecules. Ribozymes with new catalytic functions were obtained as well as RNA molecules that are resistant to cleavage by specific RNases. In addition, the catalytic specificities of group I introns, a special class of ribozymes, were modified by variation and selection. Efficient applications of molecular evolution to problems in biotechnology require a fundamental and detailed understanding of the evolutionary process. Two basic questions are of primary importance: (i) How can evolutionary methods be successful as the numbers of possible genotypes are so large that the chance of obtaining a particular sequence by random processes is practically zero, and (ii) how can populations avoid being caught in evolutionary traps corresponding to local fitness optima? This review is therefore concerned with an abridged account of the theory of molecular evolution, as well as its application to biotechnology. We add a brief discussion of new techniques for the massively parallel handling and screening of very small probes as is required for the spatial separation and selection of genotypes. Finally, some imminent prospects concerning the evolutionary design of biopolymers are presented.","PeriodicalId":7037,"journal":{"name":"Acta Biotechnologica","volume":"19 1","pages":"3-17"},"PeriodicalIF":0.0,"publicationDate":"1996-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87363926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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